The present invention relates to public display devices.
More particularly, the invention concerns a public display device comprising:
a closed external casing which defines a certain internal volume and which has at least one transparent opening,
a support band made of flexible material which is arranged in the casing internal volume, this band having at least one so-called printing side, adapted to be printed so as to comprise several juxtaposed posters along the support band,
a support band driving mechanism, this mechanism being adapted to selectively display, opposite the transparent opening, one of the printed posters on the support band.
at least one electronic interface adapted to receive digital data representing designs to be printed on the support band,
an electronic central unit communicating with the interface and controlling the support band driving mechanism,
and a printer controlled by the central unit, this printer being arranged opposite a printing zone belonging to the support band printing side, the central unit being adapted to make the printer print the designs received by the interface.
Document FR-A-2 598 539 describes an example of such a display device, wherein the printer is a two channel plotter arranged in correspondence with the external casing""s transparent opening, so that each poster is printed in front of the public.
This known display device has the disadvantage of not being able to display a complete poster to the public, whilst a new poster is being printed.
This disadvantage is all the more important because the printing time of a poster is long.
The same disadvantage exists in the display device disclosed in the document FR-A-2 629 243, which describes a similar display device: this other known device comprises two transparent openings for displaying posters, but the printing of a poster neutralizes at least one of these transparent openings for a period of about 30 minutes.
The object of the present invention is to overcome this disadvantage.
To this end, according to the invention, the printing zone is arranged so as not to be visible through the external casing""s transparent opening, the display device comprising moreover:
a buffer zone enabling a variable length of support band to be accumulated between the printing zone and the part of the support band which corresponds to the poster displayed opposite the casing""s transparent opening, this buffer zone being adapted to enable several posters to be printed in advance while holding fixed the poster displayed opposite the casing""s transparent opening,
and means to hold taut at least said part of the support band arranged opposite the casing""s transparent opening when a certain length of support band is accumulated in the buffer zone.
By means of these arrangements, the printing of one or several new posters can be made while continuing to display to the public one of the previously printed posters, and this even when the printer comprises a printing head only moveable perpendicularly to the direction of movement of the band (in this latter case, the printing of a new poster necessitates the band to be moved at the same time as the printing head is moved, but this movement of the band does not prevent continuing to display the same poster in the casing""s transparent opening, due to the fact that a variable band length can be accumulated in the buffer zone).
In preferred versions of the invention, one and/or other of the following arrangements can possibly be resorted to:
the electronic interface is a telecommunication interface,
the electronic interface is a data medium reader chosen from among optical disc readers, magnetic tape readers, magnetic disc drives, magnetic hard disc drives or semi-conductor memories,
the support band has information zones carrying codes representing data chosen from among identification data of the posters and location data of the posters, the display device comprising moreover at least one reader device which is arranged in correspondence with said information zones and which is adapted to read the printed data in these zones, this reader device being connected to the electronic central unit,
the printer comprises a printing head able to be moved in translation along two perpendicular axes, namely a first axis arranged parallel to the length of the support band, and a second axis arranged along the width of the support band,
the printer comprises a printing head only moveable parallel to the width of the support band, the driving mechanism being adapted to move the support band parallel to its length in front of the printing head during the printing operation,
the electronic central unit has in its memory at least one character font,
the external casing has a flat shape, having two parallel principal sides, at least one of which comprises said transparent opening,
the external casing has a cylindrical shape and has an annular lateral wall wherein is made said at least one transparent opening,
the electronic interface is also adapted to receive, besides data representing designs to be displayed, chronological data relating to the urgency and/or to the frequency and/or the duration of display of said designs, the electronic central unit being adapted to memorize these data, and to print and display opposite the casing""s transparent opening the corresponding posters, as a function of said chronological data.